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Ways of studying the brain - Coggle Diagram
Ways of studying the brain
fMRI
Uses a magnetic field and radio waves to monitor blood flow; it measures the change in the energy released by haemoglobin, reflecting activity of the brain to give a moving picture of the brain; activity in regions of interest can be compared during a baseline task and during specific activity
(+) No radiation/non-invasive:
unlike other techniques such as PET scans which involve the administration of a radioactive substance to the body, fMRI just measures changes in blood flow.
(+) Ethical:
Patients engaging in fMRI are likely to be in an appropriate mental state to give full informed consent.
(-) Expensive:
very costly and require specially trained operators. the cost for each participant is so high, it often means research involving fMRI scanning has small sample sizes which makes the results of any studies difficult to generalise from.
(-) Biological reductionism:
Critics argue that because of thus, the networked nature of the brain is overlooked. They argue that it is the communication between brain regions that is the most critical to mental function.
EEG
Electrodes are put on the scalp and detect neuronal activity directly below where they are placed. Differing numbers of electrodes can be used depending on the focus of the research.
Same evaluative points as ERPs
ERPs
Electrodes are put on the scalp and detect neuronal activity directly below where they are placed in response to a stimulus introduced by the researcher.
(+) Cheaper than fMRI:
Widely available to researchers and more participants can be used in research because the cost per participant is not as high. This means that sample size in such research is often larger and so the results are easier to generalise to other people.
(+) Practical Applications - clinical diagnosis:
EEGs can pick up disturbed brain activity which is associated with epileptic seizures which is helpful in diagnosing epilepsy. They have also contributed much to out understanding of the stages involved in sleep.
(-) Only reasonably accurate:
Both techniques measure brain activity via electrodes which may only pick up sufficiently strong voltage changes and not record activity deep in the brain. Other techniques like fMRI scans may therefore be more effective at studying brain activity.
Post-Mortem
The brain is examined after death to try and correlate structural abnormalities/damage to behaviour.
(+) More detailed than other techniques
: are invasive and allow direct study of the brain tissue at the level of neurons, synapses and neural circuits. They enable researchers to examine deeper regions of the brain such as the hypothalamus that may not be as accessible if using a non-invasive techniques.
(-) Ethical Issues:
require consent of the patient before death and depending on their health, participants may not understand what they are agreeing too. HM lost his ability to form memories and was not able to consent however an examination was still conducted. Some religions and cultures don't allow it.
(-) Retrospective data
: As the person is already dead the researcher is then unable to follow up in anything that may arise from the post-mortem concerning the link between brain abnormality and cognitive functioning.